Heat exchanger



K. E. REE

HEAT EXCHANGER March 31,, 1931 Filed March 27, 1928 o ofi o 0 0 0 0 0Patented Mar. 31, 1931 UNITED STATES PATENT OFFICE KENNETH B. BIS, 01'!DALLAS, TEXAS, ASSIGNOB TO THE GBISCOM-RUSSELL COMPANY,

OF NEW YORK, N. Y., A CORPORATION OF DELAWARE' HEAT axcnauenn IApplication filed March 27,1928. Serial Np. 264,998.

This invention relates to heat transfer apparatus, and particularly toheat exchangers of that type in which there is a transfer of heatbetween onefluid flowing through a 6 bundle of tubes and another fluidflowing through a'container surrounding the bundle. Thermal efficiency,or rate of heat transfer, which directly renders heatexchangers-respecially of the shell-and-tube type-pf a 10 greater orlesser industrial efficiency, depends largely on the temperaturedifierence between the tubes and the fluid surrounding the tubes. It hasbeen determined that the best 'way to secure this temperature differenceis to force thorough contact of the fluid under treatment with thetubes, and, what is equally important, to establish and maintainuniformity of thermal distribution throughout the bulk'of the fluid.

It is particularly difficult to obtain this necessary thermal efficiencywhen treating viscous fluids. For example, when heating such liquids asheavy hydrocarbon oils, the oil around the tubes may indeed becomeraised almost to the same temperature as that of the tubes, at thepoints where it contacts therewith,and thereby become limped enough;nevertheless, any heat reaching the bulk of the oil usually does so byconduction alone, and the conductivity of viscous fluids is usually verylow. The same situation arises in cooling operations, as there usuallyforms on the cooling tubes, a thick film of congealing oil or residue,preventing the bulk of the fluid from cooling. Thus the apparenttemperature is not indicative of t e actual temperaturedifi'erencebetween the fluid in the tubes and the fluid in contact withthe outer' surface of the tubes.

The apparatus disclosed in United. States Patent No. 1,525,094 toRussell C. Jones, and United States Patent No. 1,597,479 to JosephPrice, relate somewhat to this situation, and

the-present invention is adaptable to these apparatus; in fact, itconstitutes, in certain ways to be hereinafter made apparent, animprovement'on them-though, as it will appear, the present invention isjust as capable of being combined with and enhancing the exchangers bycompelling uniform distribu-- tion of heat throughout the body of thefluid by this same structure which enforces thor- ,oughnes's andcompleteness of contact.

' It is another object of the present invention to so increase thelength of the path of flow in heat-exchangers, of liquids which aredifiicult to be cooled or heated,-and which therefore necessitate alonger flow,-without thereby increasing the length of the shell or ofthe tubes, that smaller, less expensive heat exchangers can besatisfactorily used.

The invention will be described in conjunction with the accompanyingdrawings, which are to be referred to merely for the purpose of are tobe understood as not in any way limitmg the invention to the particularconstruction of shell, tubes, headers, or the other well lmown partsshown therein. In these drawlngs, v 7

Fig. 1 is a longitudinal sectional view taken centrally through anapparatus embodying the invention;

Fig. 2 is a plan view of one of the elements used in carrying out theinvention; i

, Fig. 3 is aside elevation thereof;

definitely ascertaining one typical form, and

Fig. 4 is a plan view of another element used in carrying out theinvention;

Fig. 5 is a sectional view along line 5--5' of Fig. 4, and

- Fig. 6 is an enlarged detailed view of a portion of one of the shellsshown in Fig. 1. In the drawings, the invention is shown as applied to aheat-exchanger comprising a unitary container 1 for the flow of thefluid to be treated,-usually a viscous liquid of some sort-and thiscontainer may be formed of upper and lower shells, connected at one endby an up-pass 2. These shells may be closed at one end by a twintube-plate 3 to which may be attached twin caps 4. Tubes 5 anchored byone end in the sheet 3 form a bundle in each shell, and ma terminate attheir other ends in floating ox-headers 6.

These headers 6 may be connected by a flexible down-pass 7, and coveredby a large cover-all cap 8 secured over the ends of both shells. Asuitable inlet opening 10 for the viscous liquid under treatment may beprovided on the lower arm, and a suitable outlet 9 therefor may beprovided on the upper shell. The other medium-steam or cold water,according as the viscous liquid is to be heated or cooledmay then beadmitted, in counter flow if preferred, through a suitable inlet opening12,.which may be provided therefor in the upper cap 5. A suitablecentral core 13 may be provided as shown.

The present invention contemplates forcing the liquid to be treated intoa flow-path such as that shown in Fig. 6, by the provision andemployment of a baflle made up of members such as those shown in Figs. 2and 4, these members being, further, spaced and arranged within theshell around the tubes in a particular manner, and preferablyalternately at predetermined, equal intervals along the member 13. Inorder to secure the elements of the baffle unit against vibration andother stresses set up by the rush of a heavy liquid through the shell,as Well as to help maintain the proper spacing, stay-bolts, tie-rods, orspacer bars 16 can readily be anchored in the tube sheet 3, passedthrough their peripheries at suitable places, and then secured over theother end of the bafiie, as shown in Fig. 1.

However, this manner of spacing and supporting the elements of thebaffle structure is more orless a result of the particular structure ofthe elements themselves, and is not the principal feature of theinvention, and is employed onl in order to allow the baflie elementsthemse ves to perform their particular functions, in accomplishing theobjects of the invention, and hence this arrangement may well be variedaccording to the particular circumstances.

The bafle is, as already stated, composed of two different kinds ofmembers, 14 and 15. The elements 14 may well be similar to thosedisclosed in the above mentioned Patent N 0. 1,525,094 to Russell C.Jones, and are here shown as consisting of flat metal plates perforatedwith tube holes 19 to slip over the tubes, and provided with radialslits 17, the sectors formed by these slits being then twisted in aplane perpendicular to the original fiat plane of the body, so as toform of the sectors, propeller like blades. There is also provided anaperture 20 in the center of the selves, has resulted in certainimprovements in the functioning of heat exchangers, as explained in theabove mentioned patent to Russell G. Jones but by employing the improvedtwo-element battle-structure of the present invention, the thermalefliciency and general performance of heat-exchangers is still furtherincreased.

Each element 15 comprises a flat circular plate of sheet metalperforated with a plurality of tube holes 19 to slip over the tubes andalso has holes-21 for the passage of the stay-bolts 16. At or near themiddle or central portion of the plate, there is formed or left anaperture substantially coextensive with the centres of the elements 14,which are left solid. Tubes 5 are supported by the solid or peripheralpart of the plate 15, by passing through the apertures 19, but there isa clear passageway for the fluid through the central portion 22, sincethe tubes 5 pass through the aperture 22 unsupported and thereforewithout obstructing itto any appreciable extent.

It is now clear that the fluid under treatment as it passes through themembers 14 is broken up by the fan blade action into a plurality ofidentical streams, each tending to be forced positively by thepropeller-like action of the element 14 outwardly and thencircumferentially around the outermost periphery of the tube-bundle as awhole, in a plurahty of helices. That is, the fluid then is given ageneral helical flow and this helical flow has a component forcelongitudinal of the tubes and another component circumferential of thetubes, the resultant path being an oblique movement from the center ofthe shell out to the circumference. The battle 15 then causes the fluidto flow transversely across the tubes to the center, where it passesthrough the opening 22 parallel with the tubes. Some of the fluid will,of course, pass straight through the openings between the blades of themembers 14, moving coaxially with the tubes instead of swirling out andaround the periphery of the bundle, and this is a. distinct advantagewhen the tubes are set closely to each other. All the streams, however,are suitably brought back to the region of the center-tubes, instead ofcontinuing on lengthwise, sticking to the shell inside.

In the structure of the Jones patent, the cross-currents produced ateach successive baflle element are the same as in the preceding, but inthe structure of the present a plication, a more complete mixing of theaid, a more uniform temperature throughout the entire cross section ofthe shell, and a more thorough contact of the fluid with the workingsurfaces is obtained by means of the coaction of the plates 15. That isto say, in the heat exchanger of the Jones patent, there is produced achange in direction from axial to circumferential, as the liquid passesthe successive baffles, but it is possible for the liquid at the shellsurface to follow the surfacewithout mixing with the liquid at themiddle of the shell, possibly causing pockets and dead spots to formparticularly if the liquid is viscous. By means of the elements 15 itisassured that the center tubes 5 will-also be equally thoroughly usedand contacted with by all the viscous liquid; every time it passesthrough one of the vane-plates 14 and is thrown out towards the shell,and around the tube bundle and lengthwise it is'inevitably drawn back tothe central tubes again before.

itcan pass on farther through the shell.

The fluid is thus thoroughly forced against all the'portions of the heattransferring sur face, being broken up into outflowing,circumferentially moving streams, on passing through an element 14, andimmediately thereafter being gathered together into a cen-v tral stream,on reaching an element 15, thus alternately expanding and contracting,and hence contacting with all the tubes, setting up cross-currents, andscouring each tube to remove any congealed fluid, in cooling operations;or, in heating operations, to mix the limpid film thereon with the restof the fluid, and by all these changes of direction securing increaseduniformity of thermal distribution.

After passing through, say, the lower shell 1, the fluid may be forcedup the up-pass 2 into the upper shell, where the action first describedas occurring in the lower shell is repeated, and the fluid is finallyforced out of the outlet 9, having been thoroughly treated and leavingno congealed residue on the tubes, and having a uniform finaltemperature throughout its bulk.

I claim:

1. Apparatus for the transfer of heat between two fluids, comprising acontainer for the flow of the fluid to be treated, a bundle of tubesenclosed therein for the flow of the other fluid, and a multi-unitstructure within said container and traversed by said tubes, fordirecting the fluid under treatment helically around, and thenco-axially with, said tube-bundle.

2. Apparatus for the transfer of heat between two fluids, comprising acontainer for the flow of the fluid under treatment, a bundle of tubesenclosed therein for/the flow of the other fluid, and a series ofalternately identical members traversed by said tubes and fittingagainst the inside of said conupon said fluid, a movement in a directioncircumferential of said tube bundle, a movement in a directionoblique'to the length of said tube bundle from the center of said bundleto the circumference thereof, a movement from the circumference to thecenter and a movement in a direction co-axial with said tube-bundle.

3. Apparatusfor the transfer of heat between'two fluids, comprising acontainer for the flow of the fluid under treatment, a bundle of tubesenclosed therein for the flow of the other fluid, and a multi-unitstructure "traversed by said tubesand having members.

fluid, and a series of members within said container traversed by saidtubes, alternate ones of said members having solid centers and havingtheir peripheries shaped todirect the fluid impin 'ng thereuponsimultaneously in two di erent directions, and

others of said members having solid periphcries and having their centersformed to 1 direct the fluid in a single direction.

5. Apparatus for the transfer of heat between two fluids,- coniprising acontainer for the flow of the fluid to be treated, a bundle of tubesenclosed therein for the flow of the other fluid, and a multi-unitstructure within said container and traversed by said tubes fordirectingthe fluid under treatment alternatel radially of, and co-axially withsaid tubeundle, said member comprising a multi-unit baflle, certain onesof said units being formed and placed to direct the fluid undertreatment tangentially outwards towards the shell-inside and transversesaid tubes and in a plurality of separate helical currents, andalternate ones of said units being formed and placed to interrupt theflow of said helical currents along the shell-inside,to collect saidcurrents,

and to direct said currents to and through the center of thetube-bundle.

6. Apparatus for the transfer of heat between two fluids, comprising acontainer for rents to and through the center of the tube bundle.

7. In a heat-exchanger, a container for a fluid to be treated, atube-bundle enclosed therein, and means for maintaining a hightemperature difference between the tubes and the fluid to be treated,comprising a multiunit baflle strung along the tubes from substantiallyend to end thereof, said baflie including units for splittin up thefluid passing therethrough into a bundle of separate intertwininghelical currents and directing said currents tangentially and transversesaid tubes, and units for gathering said helical currents into thecenter of the tube-bundle from their outflung paths near the'innerperiphery of the container, whereby said fluid is maintained in constantagitation around all the tubes of the heat-exchanger suflicient tothereby secure a uniform heatdistribution and a maximum temperaturedifference at the heat-transferring surface.

8. Apparatus for the transfer of heat be tween two fluids, comprising acontainer for the flow= of the fluid under treatment a bundle of tubesenclosed therein for the flow of the other fluid, and a multi-unitstructure within said container, certain ones of said units having solidcentral portions and peripheries formed and placed to thereb direct thefluid simultaneously in two irections substantially at right angles toeach other, one of the directions impressed upon said fluid beingradially outward and then circumferentially of said tube-bundle, and theother direction being parallel to the tubebundle, and others of saidunits being so placed and shaped with reference to the first as toimpress upon the fluid passing therethrough, a movement transversely ofthe tube bundle toward the center and then coaxially with the tubesthereat.

9. Apparatus for the transfer of heat between two fluids, comprising acontainer for the flow of the fluid under treatment, a bundle of tubesenclosed therein for the flow of the other fluid, and a multi-unitstructure within said container, certain ones of said units having solidcentral portions and peripheries formed and placed to thereby directthe. fluid simultaneously in two directions substantially at rightangles to each other, one of said directions being radially outward andthen circumferentially of said tube bundle, and the other beingsubstantially parallel to the tube-bundle, and the other units of saidstructure having solid peripheries and central portions so formed as todirect said fluid to and through the center of said heat-exchanger andsubstantially coaxially with said tube-bundle.

10. Apparatus for the transfer of heat be tween two fluids, comprising acontainer for the flow of the fluid to be treated, a tubebundle enclosedthereby for the flow of the other fluid, and a bafile-structure thereinhavmg means for initially impressing upon the

